The use of airbags has increased dramatically in the past decade. Federal automobile safety mandates have spurred the rapid growth in airbag production and required use. Airbags are presently being used as supplemental restraint systems for both the driver's and passenger's sides of an automobile. In the past, inflators generally relied solely on the pyrotechnic action to inflate the airbags. Recently, automobile manufacturers have begun using hybrid inflators as the inflators of choice in the restraint systems. Hybrid inflators use a pyrotechnic device to release compressed gas and this gas in turn inflates the airbag. The hybrid inflator, by adding the use of compressed air, has markedly improved airbag safety and performance.
In order for an airbag to work effectively, the airbag inflator must be securely fastened to or retained in its reaction canister. In the past, pyrotechnic type passenger side airbag inflators have been secured by a variety of secondary restraint devices, a stud and nut device being one of the more popular means of securing these inflators. Many airbag inflators are also secondarily secured by brackets placed exteriorly to the reactor canister in conjunction with such a stud and nut device. The stud and nut device has introduced several new problems, particularly when a hybrid inflator is employed. First and foremost, welding the stud and nut device to the hybrid inflator has proven to be a very time consuming task. The stud must be welded to a high-gauge steel base of the inflator. Those adept in the art can readily understand the difficulty of achieving a sufficiently strong and structurally sound weld on such a high-gauge steel base and why a high scrap rate has resulted during production thereof.
There are other concerns with current module assemblies. The stud and nut arrangement, when welded to such a base of a hybrid inflator, is subjected to a variety of shearing forces due to its location at the end of the reaction canister. Upon deployment of the airbag there is a substantial force applied to the stud and nut which secure the airbag inflator in the airbag module assembly.
Therefore an object of this invention is to eliminate the need for employing a stud and nut arrangement for retention of an inflator in a module diffuser housing. A still further object of the invention is to eliminate the need for a secondary retention bracket to retain an inflator in a module diffuser housing. It is yet another object of this invention to provide a means to retain a hybrid inflator in a module diffuser housing without the need for secondary restraint mechanisms and to permit hybrid inflators to be employed in current airbag module assemblies that previously housed pyrotechnic inflators, without the requirement for any significant modification of the airbag module assembly components.